It is known to provide communications networks having path computation elements (PCE) for computing which path resources (for example links, nodes, frequency or time slots) to select for a new path through the network. A PCE has been defined as an entity (component, application, or network node) that is capable of computing a network path or route based on a network graph and applying computational constraints. A Path Computation Client (PCC) is an entity which requests a path computation to be performed by the PCE. The PCC and PCE in a typical example communicate through the PCE communication Protocol (PCEP). PCEP operations have been defined to enable effective PCE-based path computations and, in turn, the effective use of network resources. A PCE-based architecture is described in Internet Engineering Task Force (IETF) document RFC 4655 and the PCE communication Protocol is described in RFC 4657.
Software Defined Networking (SDN) is an emerging architecture which decouples the network control and forwarding functions, enabling the network control to become directly programmable and the underlying infrastructure to be abstracted for applications and network services. A consequence of this agility and programmability is the possibility of having applications running on top of the transport SDN controller which automatically requests network resources without manual intervention.
One possible type of network has a plurality of tenants. For example, a large telecom provider has a network which serves a plurality of smaller telecom providers. In this disclosure this type of network is called a multi-tenant network. The network can have a plurality of SDN controllers and, as a consequence, a plurality of different PCEs.
The present disclosure seeks to provide an alternative way of operating a multi-tenant network.